Fix indexing with StepRanges at infinity

[DanielVandH]

Needs JuliaLinearAlgebra/InfiniteLinearAlgebra.jl#190 to be merged before the tests will pass here.

Fixes #88.

[DanielVandH]

No idea what the deal is with the segfaults on macOS (not reproducible on Windows) but it's hanging on ubuntu because

(HarmonicOrthogonalPolynomials) julia> JR = Block.(OneTo(Integer(+∞)))
BlockRange(Base.OneTo(ℵ₀))

(HarmonicOrthogonalPolynomials) julia> maximum(JR) # hangs
WARNING: Force throwing a SIGINT
ERROR: InterruptException:
Stacktrace:
  [1] _foldl_impl(op::Base.BottomRF{typeof(max)}, init::Base._InitialValue, itr::BlockArrays.BlockRange{1, Tuple{…}})
    @ Base .\reduce.jl:63
  [2] foldl_impl(op::Base.BottomRF{typeof(max)}, nt::Base._InitialValue, itr::BlockArrays.BlockRange{1, Tuple{Base.OneTo{…}}})
    @ Base .\reduce.jl:48
  [3] mapfoldl_impl(f::typeof(identity), op::typeof(max), nt::Base._InitialValue, itr::BlockArrays.BlockRange{1, Tuple{…}})
    @ Base .\reduce.jl:44
  [4] mapfoldl(f::Function, op::Function, itr::BlockArrays.BlockRange{1, Tuple{Base.OneTo{…}}}; init::Base._InitialValue)
    @ Base .\reduce.jl:175
  [5] _mapreduce(f::Function, op::Function, ::IndexCartesian, A::BlockArrays.BlockRange{1, Tuple{Base.OneTo{…}}})
    @ Base .\reduce.jl:450
  [6] _mapreduce_dim(f::Function, op::Function, ::Base._InitialValue, A::BlockArrays.BlockRange{1, Tuple{…}}, ::Colon)
    @ Base .\reducedim.jl:337
  [7] mapreduce(f::Function, op::Function, A::BlockArrays.BlockRange{1, Tuple{…}}; dims::Function, init::Base._InitialValue)
    @ Base .\reducedim.jl:329
  [8] _maximum(f::Function, a::BlockArrays.BlockRange{1, Tuple{Base.OneTo{…}}}, ::Colon; kw::@Kwargs{})
    @ Base .\reducedim.jl:987
  [9] _maximum(a::BlockArrays.BlockRange{1, Tuple{Base.OneTo{Infinities.InfiniteCardinal{0}}}}, ::Colon; kw::@Kwargs{})
    @ Base .\reducedim.jl:986
 [10] maximum(a::BlockArrays.BlockRange{1, Tuple{Base.OneTo{Infinities.InfiniteCardinal{0}}}})
    @ Base .\reducedim.jl:982
 [11] top-level scope
    @ REPL[36]:1
Some type information was truncated. Use `show(err)` to see complete types.

since the call chain is

getindex(P::MultivariateOrthogonalPolynomial{D}, xy::StaticVector{D}, jr::AbstractVector{<:Integer}) where D = P[xy, Block.(OneTo(Integer(findblock(axes(P,2), maximum(jr)))))][jr]
getindex(P::MultivariateOrthogonalPolynomial{D}, xy::StaticVector{D}, JR::BlockRange{1}) where D = P[xy, Block.(OneTo(Int(maximum(JR))))][JR]

I would think that maximum(JR) = Block(ℵ₀) would be a good definition. Could that also go in InfiniteLinearAlgebra.jl @dlfivefifty (unless you have a better workaround for this that avoids a new method)? Technically piracy but I don't see things for infinities in BlockArrays

[dlfivefifty]

MacOS failure is a known issue with FastTransforms.jl (@MikaelSlevinsky any updates on this?)

I think just remove the MacOS tests for now.

[dlfivefifty]

I would think that maximum(JR) = Block(ℵ₀) would be a good definition. Could that also go in InfiniteLinearAlgebra.jl

As of InfiniteArrays v0.15 it would go in InfiniteArraysBlockArraysExt.jl

[DanielVandH]

I made JuliaArrays/InfiniteArrays.jl#211

[DanielVandH]

Not really sure the best way to fix the stackoverflow here. Might just have to come back to this at some point